Closure for pressure vessels



Sept. 1, 1931.

A. SAPORTA CLOSURE FOR PRESSURE VESSELS Filed NOV. 22, 1929 2 Sheets-Sll'xeet l Sept. l, 1931. A, SAPORTA 1,821,726

' cLosURE FOR PRESSURE vEssELs Filed Nov. 22, 1929 2 Smeets-sneer 2 A/er/a @porfa by ma A /fb'mey Patented Sept. 1, 1931 I PATENT OFFICE ALBERTO SAPORTA, OF MILAN, ITALY CLOSURE FOR- '.PRESSURE VESSELS Application led November 22, 1929, Serial No. 409,178, and in Italy lNovember 23, 1928.

The .present invention relates to a safety and guarantee closing arrangement for ves-V sels 1n which a pressure exists or 1s generated,

and especially for quick cooking pressure.

pots.

The novel closing arrangement removes the danger of explosions due to the safety valve failing to operate and prevents the vessel from being opened if the pressure of the Huid lo has not first sunk down to a value which is no longer dangerous for the attendant.

The arrangement according to the invention is essentially distinguished by the fact that it comprises at least one, preferably spiral, conveniently calibrated spring counteracting, through suitable intermediate parts, the inner pressure that tends to raise the ves sel cover, so that when this pressure overcomes the reaction of the spring the cover is raised and lets the steam escape.

A further characteristic feature of the invention is that the member securing the closure of the vessel is combined with a device which, in consequence ofthe pressure existing inside the vessel, prevents the cover from being operated by the attendant as long as the pressure is too high, whereas when the pressure has sunk -down to a convenient value the said device releases the lock and allows the :i0 cover to be opened. p

The accompanying drawings illustrate an embodiment and' some modifications of the device according to the invention by way of example only. i,

Fig. 1 is a part vertical center section through the upper portion of a 'pressure pot litted with a first embodiment of the closing arrangement applied between the lidl and the usual crossbar, and of a device intended to i0 prevent the pot from being opened as long as the pressure prevailing therein is still dangerous for the attendant.

Fig. 2 is a similar projection of a very ady vantageous modiied construction.,

Fig. 3 shows a modied constructionof the device preventing the untimely openlng of the pot, with means for optically indicating that the prevailing pressure is still dangerous.

Figs. 4 and-5 schematically show further modified constructions of the resilient closing device.

Figs. 6 and 7 show further modifications of the device controlling the opening of the pot'.

With reference to Fig. 1, the usual cross or diametral rigid bar for closing or locking the pot lid 10 is replaced by. a bridge-like crossbar 1 having, as in all pressure pots, an end portion 1 adapted to be engaged in 60 the aperture 3 of a lug 3 iiXed to the pot 4 and to beretained therein by a nose 2. The opposite end portion 1 of the crossbar 1 is acted upon by a screw 5 screwed in a block 6 invariably secured to the Shanks 7 depending therefrom and adapted to swing about'a pivot 8 inserted in a lug 9 secured to the pot.

Underneath the raised center portion of the bridge-like crossbarv 1, a split steel ring l1 is arranged, the ring being secured (for instance in the mannerv shown in Fig. 1) to the center portion of the crossbar at the top, while at the bottom the ring is secured to the center of the lid 10, Ithe lid center portion being preferably thickened or otherwise strength- 75 ened. The ring resista-nce to contraction should be tested in advance, in order to make sure that the ends of the split ring can move nearer to each other when the ot pressure has reached a value still below t e exploding 80 value.

Owing to this', as the crossbar end portions l and 1 are not in touch with the lid 10, the lid is capable to be raised as much as is 'required to let the excess steam escape, after which the ring 11wi11 resume its former position and automatically restore the closed conditions of the pot.

The device controlling the opening of the pot, signalling the presence of a pot pressure that would make an immediate opening dangerous, and opposing itself in such a case `to the screw 5 being turned in pot opening d1- rection, comprises a member which traverses the pot lid and which the pot pressure tends to force outwardly. The outerend of this member acts upon a further (sliding on the like) member normally held in rest position, in order to bring it into a position in which it prevents the screw`5 from turning in a weight eventually provided for this purpose; the

direction that would release the lid 10. The screw 5 has attached to it the wings 19, yet with a certainclearance in respect to its revolving movement for the purpose that will be indicated below. The member in question may constitute the optical signalling apparatus. or it may be connected up to the latter and be actuated .along with it.

To the underside of the lid 10, a hollow cylinder 12 is secured in any convenient manner, the bottom end of the cyiinder being closed bya perforated plug 13 or by a ring supporting a wire net with line meshesl in order to prevent the pot contents from entering the cylinder. In the cylinder 12 plays a piston 14, the spindle 15 ot which extends to the outside through a hole vpierced in the lid 10 and terminates with an expanded head 16 at the top. A packing 17'is interposed between the piston 14 and the lid 10 in order to prevent leakage.

In the end portion 1 ot the crossbar 1 a hole is pierced for reception of a sliding pin 18; this pin slightly exceeds in length the thickness of the crossbar and is preferably provided with expanded ends working as stops. `Wheu the lid 10 is applied, the eX- panded head 16 of the piston spindle 15 lies on the extension of the axis of the pin 18, and when a pressure obtains in the pot this pressure raises the piston 14 and therewith also the pin 18 resting on the head 16 ot the piston spindle 15. The top expansion of the pin 18 will thus be brought in the pathoi` the wings 19 of the screw 5 so as to prevent the latter from being turned in opening direction, viz. in the direction of releasing the pressure it exerted on the crossbar end portion 1.

When the pot pressure ceases, the piston 14 drops to the bottom either through its own or through the action of a spring pin 18 `.will thendrop too, thus releasing the wings 19 and allowing the screw 5 to be turned in pot opening direction.

It will readily be seen that the movement of the pin 18 may be utilized to actuate a swinging member adapted to supply anoptif cal indieriony of the pressure existing in the pot, the said swinging member resuming its i former position as soon as the pin .18 is free i to drop.

With Ireference tot-Fig. 2,.the lid 10a is locked on the pot 4a by a crossbarA 1a, one

. end of which is inserted in a hole formed in the lug 3a, while its other end is inserted in -aihole formedA in an arm 7 a pivoting about and combined iwith a locking device consting in a pressure screw 5a. The-crossbar nnade- 1n two halves la and 1a each of .{lwhich has a projection 33 the two projections v-'flare conjugated and bear against a corresponding 593534 Pl'm'ided on the lid. Opposite the projections 33, each crossbar half has a surface 35,v and the two surfaces 35 are traversed by a bolt 36, the bolt being surrounded by two pressure springs 11a which torce the two surfaces 35 against one another and thus stiifen the crossbar.

Then a pressure d evclops in the pot 40: tending to raise the lid, the crossbar prevents the lid from rising because the pressure of the springs 11./1l prevails over the pot pressure and maintains the deformable system 1a1a in undetormcd conditions. When, however, the pot pressure attains a determined value, the upward pressure exerted by the lid on the projections 33 causes the crossbar halves la and lcto swing through a certain angle about the lug 3a and arm 7a. as swinging centers and moves the surfaces 35 away from each other against the action ot the springs 11a. The lid will therefore be lifted and act like a safety valve.

Of course in practice, instead of springs arranged (as in the example shown) with their axis parallel to the lid, differently orientated springs might be used. Instead oli-being divided into two halves, bar might consist of a single piece or of more than two pieces. The crossbar might also be replace-d by an equivalent constructive member. The locking member might act upon the lid through the more springs arranged in the center or at the periphery of the lid, with their ends acting directly or otherwise between the locking member and the lid. Further the locking device may be `made resilent by means of springs of different type or by means of parts loa-ded by pressure or tension springs,or by means of pistons working in any desired manner etc. For instance the medified construction illustrate-d in Fig. 4 comprises two 7 springs 11b with one end fixed to the crossbar and with their other end bearing on the center of the lid 10'0. y

In the modilied construction illustrated in Fig. 5 the crossbar 10 is fast with a blade spring 110, the centervof which bears against the lid 10a. t

The screw 5 shall be fitted with a stop limiting the stroke of the screw in such a manner that the springs shall come into action only after the pot pressure has attained apredetermined value.

Also for'the device controlling the opening ofthe pot several convenient modications may be thought out, for instance the one illustrated in Fig. 3. Here the piston the cross- 146, through the intermediate of its spindles Y 45 the stem 150 will sink intoa position where it prevents the turning of the screw 56 in the same manner as in the case already explained in connection with Fig. 1.

According to a further modification illustrated in Figs. 6 and 7, a hollow block 120 is fitted in a hole provided in the lidand eX- tends past the lid to the outside. In the projecting portion of the block, an inclined 10 groove 25 is formed for engagement by a pin 35 projecting from a ring 29 threaded v upon the said projecting portion, the ring being provided with a handle 30.

The cylindrical boreof the block 120 is traversed by a stem 150 somewhat exceeding the length of the said bore; the stem carries at its top a head 16o with plane underface, and at its bottom it carries a truncated cone 140. Between the 'plane underface of the 20 head 16e andthe top face of the ring 29 a A washer 32( is interposed.

The object of the cone 140 is to secure tightness when either the pot pressure acting on the underface of the cone or the rotation imparted to the ring 29 so as to bring it from the position shown in Fig. 6 to the positionr shown in Fig". 7, causes the stem to occupy its highest4 position.

In order to close the pot, the stem 150 3o should be brought from the position shown in Fig. 6 to the position shown in F ig.7 (by turning the ring 29 in the manner already stated). After removing\ the pot from the fire, if it be desired to check Whether adangerous pressure still prevails inside, the ring 29 should be restored into the position indicated in Fig. 6. If a dangerous pressure is still present, this pressure acting on the yunderfacel of the cone will maintain the stem 150 in raised position, whereby the stem 'head 160 will maintain the abovesaid locking parts in locking position and prevent the turning of the screw'5 in pot opening direction. According as the pot pressure sinks,

into the position indicated in Fig. 6, thus releasing the locking parts. The sinking of the stem 15o may be assisted bv a spring or by weights.'

Eventually the bottom end of the stem 150 and cone 140 may be enclosed in a lchamber Y similar to the chamber 12 of Figs. 1 and 3, the chamber bottom end being closed by a perforated spring or by wirenet with fine meshes.

In Fig. 3 means are shown intended to secure that the screw 5 shall exert its pressure on the end portion 1 ofthe crossbar 1.

Such means essentially consist in a convex spherical projection 26 provided on the top J0 face of 1 and cooperating with a, corresponding concavity 27 formed in or secured to the end of the screw 5b. Alternatively the bottom end of the screw 5b may be spherically shaped,.and a'spherical recess to suit be formed in the top face of l. This arrange- 'a certain clearance in the direction of rotation in order to avoid that the end position of the wings 19 should never accurately coineide with the member intended to prevent the turning of the screw in opening direction.

Of course the pot according to the invention is equipped with a whistle safety valve I and with other fixtures.

What I claim and desire to secure by United States Letters Patent is:

1. In a pressure cooking or like vessel including a closure member, a retaining member normally holding said closure member in closed position said retaining member comprising a plurality of relatively movable parts and spring meansnormally maintaining said parts from relative movement until the pressure in the vessel overcomes that of the spring means.

2. ln a pressure cooking or like vessel including a closure member, a closure retaining member formed of two juxtaposed relatively movable parts and sprihg means holding said parts against relative movement until the pressure within the vessel acting through the closure member overcomes the action of the spring means.

3. In a pressure cooking or like vessel including a closure member, a closure retaining'device consisting of a cross member in two parts each provided with a flange, a bolt joining said flanges and opposed springs surrounding said bolt and acting on said flanges to hold the said two parts together until the pressure in the vessel overcomes the action of saidspringsfand permits relative movement of said two vice.

ALiiERTo sAPoRTA.

parts I,of the retain/ing de- 

